Pierce unit hydraulic control



April 1966 F. M. WILLIAMSON 3,244,051

PIERCE UNIT HYDRAULIC CONTROL Filed Jan. 31, 1964 5 Sheets-Sheet 1 I INVENTOR. f/ay/M l z /in'avasvrz.

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PIERCE UNIT HYDRAULIC CONTROL Filed Jan. 31, 1964 3 Sheets-Sheet 2 April 5, 1966 F. M. WILLIAMSON 3,244,051

PIERCE UNIT HYDRAULIC CONTROL Filed Jan. 31. 1964 3 Sheets-Sheet 5 I INVENTOR.

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J 770 Fur/st United States Patent 3,244,051 PIERCE UNIT HYDRAULIC CONTROL loyd M. Williamson, Detroit, Mich, assignor to Di -Bro Engineering Company, Detroit, Mich, a corporation of Michigan Filed Jan.- 31, 1964, Ser. No. 341,503 6 Claims. (Cl. 83588) This invention relates to pierce unit hydraulic controls of the type generally disclosed in my prior Patents No. 3,089,375, issued May 14, 1963, for Hydraulically Actuated Piercing Unit, and No. 3,016,707, issued Ian. 16, 1962, for Hydraulic System for Fabricating Dies. The invention of the instant application is an improvement over that disclosed in my prior copending application Ser. No. 91,362, now Patent No. 3,147,657, filed Feb. 24, 1961, for Hydraulically Actuated Piercing Unit, of which the present application is a continuation-in-part, such copending application in turn being a continuation-in-part of the applications upon which Patent No. 3,089,375 is based.

The present invention has reference to certain new and useful improvements in hydraulic piercing systems whereby the tool of the pierce unit may be hydraulically and rapidly actuated in both directions and wherein the pressure applied in moving such tool in one direction is independent of that applied for moving it in its other direction. The present invention also provides a system which is very flexible whereby it may be readily adapted to meet a wide variety of conditions.

A principal object of the invention is to provide a new and improved pierce unit hydraulic control.

Other and further objects of the invention will be apparent from the following description and claims and may be understood by reference to the accompanying drawings, of which there are three sheets, which by way of illustration show preferred embodiments of the invention and what I now consider to be the best mode of applying the principles thereof. Other embodiments of the invention may be used without departing from the scope of the present invention as set forth in the appended claims.

In the drawings:

FIGURE 1 is a schematic view of a pierce unit hydraulic control system embodying the invention, with certain parts shown in section;

FIGURE 2 is an enlarged sectional view of the pierce unit per se; and

FIGURE 3 is a view similar to FIGURE 1 of a modified system.

As illustrated in FIGURE 1, the system in general comprises a pierce unit 10, a valve 12, a tank of hydraulic fluid i4, and a booster unit 16 interconnected in a hydraulic circuit for supplying hydraulic fluid under pressure to the pierce unit for advancing the tool thereof. The system of FIGURE 1 further includes another valve 20, a tank of hydraulic fluid 22, and a booster unit 24 which are interconnected in the hydraulic circuit for supplying hydraulic fluid under pressure to the pierce unit for retracting the tool thereof. The tanks should be mounted at an elevation above the pierce units and the boosters. The pierce unit preferably comprises the construction illustrated in FIGURE 2. A cycling valve 26 is associated with the booster 16 for regulating the supply of compressed air thereto for energizing the booster l6, and

a similar cycling valve 28 is associated with the booster 24, the cycling valves 26 and 28 being arranged to be alternately actuated for effecting the feed and retraction of the tool of the pierce unit.

As illustrated in FIGURE 2, the pierce unit comprises a cylinder 40 provided at one end with a guide 42, the

3,244,051 Patented Apr. 5, 1966 bore 43 of which forms a sliding support for the enlarged head 44 of a tool holder indicated generally at 46. The guide 42 is removably fixed to one end of the cylinder 40 and a cap 48 is removably fixed to the guide 42. The tool holder 46 includes a shank 50 which projects into the bore 5'2 of the cylinder where it is secured to a piston 54 by bolt 56. The other end of the cylinder 40 is closed by a cap 58 to which the hydraulic fluid pressure line 60 is connected. The line 66 communicates with a passage 62 in the cap 58 which communicates with the cylinder bore 52 on one side of the piston 54, the latter being shown in its retracted position. The joint between the cap 58 and the cylinder 49 is gasketed by a seal, such as an O-ring 64, and the piston 54 is provided with sealing rings 66 and 63.

A shaft seal cage 79 is secured within the cylinder bore 52 adjacent the guide 42 and is provided with an annular sealing ring 72 for cooperation with the cylinder bore 52 and an annular seal '74 for sealing engagement with the shank 5i) of the tool holder 46. The cage 76 is suitably anchored in the position illustrated and along with the guide 42 serves to slidably support the tool holder 46. A stop collar 76 is seated within the bore 52 adjacent the cage 70 and is provided with an aperture for accommodating the shank 50 of the tool holder. A coil spring 73 is confined between the collar 76 and a washer 80 which abuts the forward face of the piston 54 and serves to bias the piston 54 and the tool holder 46 afiixed thereto to their retracted position.

A hydraulic fluid pressure line 82 is connected to the cylinder 46 and communicates with a passage 84 whereby hydraulic fluid under pressure may be supplied to the cylinder bore 52 to react on the piston 54 for returning it to its retracted position. A washer 86 is confined by and between the cap 48 and the guide 42 and includes an integral lzey 88 which projects into a longitudinally extending groove 90 in the enlarged portion 44 so as to prevent rotation thereof. When the bolts 92 which clamp the cap 48 to the guide 42 are loose, the tool holder 46 may be rotated about its axis so as to properly orient the tool 94 with the work, this adjustment being accomplished by using a hand tool on the projecting end of the tool or punch 94 so as to rotate the tool holder 46 to the desired position. Thereafter the bolts 92 are tightened so as to lock the tool holder and the tool 94 carried thereby against rotation. The tool holder 46 includes a socket 1% in which the shank of the tool 94 is seated and retained by a setscrew 102 which is threadedly positioned in a tapped hole in the tool holder 46 whereby the tool 94 may be secured in the socket and removed therefrom. A stripping nose 104 is slidably secured on the end of the tool holder 46 and biased to its extended position by a spring 106 which is confined between the tool holder 46 and the inside end of the nose 104. The tool securing end of the pierce unit construction is disclosed and claimed in my prior application Ser. No. 294,427, filed July 11, 1962.

The length of the stroke of the tool 94 is determined by the distance between the piston 54 and the collar 76, and where different travel is required a cage 76 or collar 76 of different axial length than the one illustrated may be employed. The collar 76 backed up by the cage 76 thus forms a stop for limiting the feed stroke of the tool 94 under the hydraulic fluid pressure applied to the back face of the piston by fluid introduced into the cylinder 52 through the port 62. The spring 78 and hydraulic fiuid under tank pressure supplied to the cylinder bore 52 through the fluid line 82 react on the piston 54 for retracting it and the tool 94 with a force considerably in excess of the tank pressure normally applied through line 60 so that the tool 94 is normally retracted.

The tank 14 is supplied with hydraulic fluid under pressure, say for example -40 lbs. per square inch (preferably about one-half the air pressure supplied to tank 22), through the air pressure line 110, and the pressure, in the tank is maintained and regulated by the valve 112. The tank contains a quantity of hydraulic fluid under such pressure which is supplied to the booster 16 and to the cylinder 52 of the pierce unit 19 for eflecting the feed stroke of the tool. 94. The tank '14 is connected by hydraulic fluid pressure line 116 to a passage 118 in the valve 12. The passage 126 communicating at one end with the passage-118 communicates with a a passage 122 past a check valve 124, the check 'valve serving to permit hydraulic fluid flow from the passage 120 into the passage 122, but'not in the reverse direction. The passage 126 in the valve 12 interconnects the passage 122 and. a hydraulic fluid pressure line 128 whichleads to the hydraulic fluid cylinder (not shown in detail) of the booster 16. The booster 16 may be of the construction disclosed in my prior application Ser.

' No. 91,362 and includes, in addition to the hydraulic cylinder an air cylinder of larger size which when en,

ergized'is effective to energize the hydraulic cylinder so 'asjto dischargehydraulic'fluid from the booster 16 ate pressuremany times that prevailing in the tank 14,, The

I air' cylinder of the booster 16 may haveia-diameter'tefi. times that 'of the hydraulic cylinder, with the result that when the beoster16; is energizedgthe. hydraulic fluid dischargedtrom' the hydraulic fluid'cylinder will be discharged under apressure ten times that of the air'pres sure applied to the air cylinder of the booster, and'if such air pressureis 100 lbs. per square inch, the booster Will discharge hydraulic fluid lbs. per square inch. 7 V The hydraulic cylinder of the booster is charged with hydraulic fluid from the tank 14 when the booster is under a pressure or" 1000 deenergized, the pressure on the hydraulic fluid in the tank serving-to recharge the hydraulic cylinder of the booster andto retract the air piston thereof. The supply of air under pressure to the booster 16 is controlled 7 'by the cycling valve 26 which is adapted when actuated to openthe airpres'sure line 111 thus permittingthe apr I plication of air pressure to the air cylinder of the booster '16 for :energizing the booster.

. When the cycling valve 26 returns to its normal position,it shuts 011 the air supply to the booster'16'and vents the air under pressure previously supplied thereto so as to deenergize the booster hydraulic cylinder thereof will retract and oil under tank pressure will flow from the tank 14. to the hydraulic cylinder of the booster for recharging the same.

The passage 118 in the valve 12 communicates through 'a normally open; valve 130 with passage 134 which is 016.; Upon the. deenergization of'the' booster 16 the I in open' communication with the oil line leading to the cylinder bore of the pierce unit 10 so that oil under 1 .tank pressure is supplied to the cylinder bore 52'through the passage 62, but the tank pressure on such oil is inadequate to move the piston 54 against, the resistance 0f the spring 78 and the hydraulic pressure supplied" through line 82. The'valve 130 comprises a sleeve 136 seatedin valve chamber 138 and a piston type valve 140 which is slidable within the sleeve, 136 and biased When the booster 16 is energized, the hydraulic fluid discharged thereby reactson the piston valve'member 140 to shift the same so as to uncover the ports 146v whereby the hydraulic fluid discharged by the booster is supplied through passages 144, 132, 134 and line 60 t0 the cylinder bore 52 of the pierce unit 10 for eflecting the feed stroke of the pierce unit. The shifting of the piston valve member 140 in' response to the discharge tion or return stroke of the tool 94 of the pierce unit.

The cycling valve 28 preferably is actuated in response to the completion of the feed stroke of the tool 94; that is,'a sensing device responsive to the completion of'the feed stroke of the tool 94 'maybe employed to actuate '(i.e., open) the cycling valve.28 so as to energize the booster -24. as soon as the feed stroke of the tool 94 is completed so as to effect'the immediate retraction and stripping stroke of'thc' tool 94. The cycling valve 28 is the same type as the cycling valve 26, the'booster 24 7 is of the same construction as the booster 16, the tank '22 is of the same jconstruction'as the tank 14, and the valve 20 is of the same construction as the valve 12; and the tank 22,,valve 2d, and booster 24 are hooked up in a hydraulic circuit in the same way as the corresponding elements 12, 14 and 16 and will function in the same way. However, the pressure maintained in thetank 22 preferably is higher and adjusted independently of the pressure in the tank 14, and the booster 24 may be larger or smaller than the booster 16 so that the pressure available on the feed stroke of the tool 94 may be greater or less than the pressure available for retracting the tool 94. When spring 78 is adequate to effect the retraction of tool 94'against the hydraulic pressure supplied from tank 14, tank pressures on both of the circuits may be the same and a'common pressure tank may :be

employed, although for eflicient retraction and stripping and other reasons I prefer to use a pressure in tankj22j sufliciently high .to overcome the difference. in effective area on opposite sides of piston 54.

The cycling valves'26 and 28'forthe boosters 16 and V 24 are normally, closed or inactive'so thatthe boosters 16 and 24 are normally deenergized'so that the system will normally be in the position as illustrated in FIG- URE 1. The cycling valve 26 may be actuated in any suiable way, such for example as in response to'a sensing .and'power moved in bothdirections so as to makeit pos sibleto achieve rapid piercing of successive blanks. In fact,

' the tool 94 maybe reciprocated with such rapidity that .to" the position illustrated by spring 142; The valve chamber 138 intersects the passage 118 and also a pas sage 144 which communicates with one end of the passage 132.

The sleeve 136is provided with ports which are in line with the passage 118 whereby in the position of the V valve .130 as shown, oil is free to flow through such ports into the interior of the sleeve 136- and thence into the passage 134. The sleeve 136 is also provided with ports a 146 in "line with the passage 144, but such ports are normally closed by the piston valve 148 which seats on the end-of the chamber 138 and around a shoulder provided by a port 150 which communicates with the passage 122.

the recharging of the hydraulic cylinders of the boosters 16 and 241is expedited by the hydraulic fluid displaced from the cylinder bore 52 of the pierce unit through passages 113 and due to the fact that spring 142. opensv valve as soon as booster 16 is deenergized. It will be evident that ,oil under tank pressure is always available for supply to the hydraulic cylinders of the, booster units 16 and 24 and. the cylinder bore 52 of the pierce unit 10 so as to make up for any leakage around the piston 54 and the pistons of'the booster units 16 and 24.

' If hydraulic pressure return of the tool 94 is not desired,

the means for tripping or actuating the cycling valve 28 may be removed or the circuit which includes the valve 20, booster 24, and tank 22 otherwise disabled whereby the spring 78 will be effective to retract the tool holder 46 and the tool 94 carried thereby. The spring 78 is not required where hydraulic fluid pressure in tank 22 is adequate to retract the piston 54, but the spring does serve to locate the stop collar 76 adjacent the seal cage 70 and to compensate for the area differential on opposite sides of piston 54, and where hydraulic retraction pressures are adequate the spring 78 can be a very light spring. However, when the spring 78 alone is used for retraction, a much heavier spring is required.

In the modification of FIGURE 3, the pierce unit and the hydraulic system for effecting the retraction thereof, including the valve 20, booster 24 and the feed tank 22 are the same as in FIGURE 1. However, the system for effecting the feed stroke of the tool is actuated differently but operates in the same way as the system which includes the valve 12, the booster 16, and the pressure tank 14 of FIGURE 1. The pressure tank 214 for the feed part of the system in FIGURE 3 may be the same as in FIGURE 1. The valve 212 includes all of the mechanism of the valve 12 plus a pressure relief valve which is indicated at 215, and instead of using an air pressure operated booster such as 16 to supply the pressure required for effecting the feed stroke, such pressure is supplied by a booster cylinder 216 and piston 217 actuated by the ram 218 of a press, as shown in FIG. 1 of my Patent No. 3,089,375. The cylinder 216 is supplied with hydraulic fluid pressure from the tank 214 through the fluid pressure line 228 which is connected to the valve 212, and the tank pressure normally biases the piston 217 to its upper position. However, upon the closing of the press ram, the piston 217 is moved so as to displace hydraulic fluid from the cylinder 216 which is supplied through the line 228 to the valve 212 and thence to the pierce unit 210 in a manner similar to that described in connection with the valve 12. For convenience, the parts of the valve 212 which correspond to the valve 12 are indicated by the same reference characters.

When the press ram 218 reaches the bottom of its stroke, the oil flow to the cylinder of the pierce unit stops and the spring 142 of the balance valve moves the valve piston to open the ports in sleeve 136 which communicate with passage 118. This allows free flow of oil from the pierce unit to the tank and prevents a hydraulic lock between the pierce unit and the cylinder 216, allowing fast return of the piston 54 and the tool 94 for stripping.

Since the ram-actuated piston and cylinder 217, 216 are capable of developing tremendous pressure in the system, a pressure relief valve 215 is included in the valve 212 so as to dissipate excess pressure in the event that the feed stroke of the pierce unit is completed before the ram 218 reaches the bottom of its stroke. The pressure relief valve essentially is of the construction illustrated in my patent Reissue 25,027. The pressure relief valve 215 essentially provides a pressure relief by-pass between passage 122 on the high pressure side of the system and passage 118 on the low pressure side when the valve 130 is closed so as to prevent the generation of dangerous pressures on the high pressure side of the system. The pressure relief valve of course may be adjusted so as to set the bleed-off pressure at any desirable pressure, and such pressure will then be the maximum pressure that can develop on the high pressure side of the system.

While I have illustrated and described preferred embodiments of my invention, it is understood that these are capable of modification, and I therefore do no wish to be limited to the precise details set forth but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. A hydraulically actuated pierce unit comprising a hydraulic cylinder having a piston reciprocable therein and a piercing tool connected to said piston so as to move therewith, a first hydraulic circuit connected to said cylinder on one side of said piston for supplying hydraulic fluid under pressure thereto for moving said piston in one direction, a second hydraulic circuit connected to said cylinder on the other side of said piston for supplying hydraulic fluid under pressure thereto for moving said piston in the opposite direction, each of said circuits including a tank of hydraulic fluid under regulated pressure and a hydraulic pressure booster connected in fluid flow and pressure transmitting relation to each other and to said cylinder so that said cylinder and said booster are supplied with hydraulic fluid under tank pressure, and a valve in the hydraulic connection between said cylinder and said tank which is arranged to close upon energization of said booster to prevent the transmission to said tank of pressure generated by the energization of said booster, said valve including a spring biased valve member normally positioned to provide fluid flow from said cylinder to said tank upon deenergization of said booster, the pressure in the tank of the circuit for effecting the retractile stroke of said tool being substantially higher than the pressure in the other tank so that said tool is normally retracted when said boosters are deenergized.

2. Apparatus according to claim 1 wherein the fluid flow and pressure transmitting connections of each of said circuits comprise a one-way fluid flow connection from said tank to said booster, a one-way fluid flow connection from said booster to said cylinder, and a two-way fluid flow connection between said cylinder and tank and wherein said valve is closed in response to hydraulic fluid discharged by said booster upon energization thereof.

3. A hydraulically actuated pierce unit comprising a hydraulic cylinder having a piston reciprocable therein and a piercing tool connected to said piston so as to move therewith, a first hydraulic circuit connected to said cylinder on one side of said piston for supplying hydraulic fluid under pressure thereto for moving said piston in one direction, a second hydraulic circuit connected to said cylinder on the other side of said piston for supplying hydraulic fluid under pressure thereto for moving said piston in the opposite direction, each of said circuits including a tank of hydraulic fluid under regulated pressure and a hydraulic pressure booster connected in fluid flow and pressure transmitting relation to each other and to said cylinder so that said cylinder and said booster are supplied with hydraulic fluid under tank pressure, and a valve in the hydraulic connection between said cylinder and said tank and booster which is operable upon energization of said booster to shut off the flow connection between said cylinder and said tank, said valve including a spring biased valve member normally positioned to provide open two-way fluid flow between said cylinder and tank when said booster is deenergized.

4. Apparatus according to claim 3 wherein said boosters are energized alternately.

5. A hydraulically actuated pierce unit comprising a hydraulic cylinder having a piston reciprocable therein and a piercing tool connected to said piston so as to move therewith, a first hydraulic circuit connected to said cylinder on one side of said piston for supplying hydraulic fluid under pressure thereto for moving said piston in one direction, a second hydraulic circuit connected to said cylinder on the other side of said piston for supplying hydraulic fluid under pressure thereto for moving said piston in the opposite direction, each of said circuits including a tank of hydraulic fluid under regulated pressure and a hydraulic pressure booster connected in fluid flow and pressure transmitting relation to each other and to said cylinder so that said cylinder and said booster are supplied with hydraulic fluid under tank pressure, and a normally open valve in the hydraulic connection between said cylinder and said tank which is arranged to close in response to energization of said booster to shut off the fluid flow connection between said cylinder and said tank, said valve including a spring biased '2 valve member normally positionedzto provide :fluid flow from said cylinder to the tank when said booster is deenergized.

6. Apparatus according to claim. 5 wherein said pierce unit includes a spring biasing said piston to its-retracted position whereby said piercing tool may be retracted by 8 said spring when the hydraulic circuit operable for retracting said tool is inefiective.

No references ,cited.

5 WILLIAM DYER, JR.,'PITim(ll'y Examiner. 

1. A HYDRAULICALLY ACTUATED PIERCE UNIT COMPRISING A HYDRAULIC CYLINDER HAVING A PISTON RECIPROCABLE THEREIN AND A PIERCING TOOL CONNECTED TO SAID PISTON SO AS TO MOVE THEREWITH, A FIRST HYDRAULIC CIRCUIT CONNECTED TO SAID CYLINDER ON ONE SIDE OF SAID PISTON FOR SUPPLYING HYDRAULIC FLUID UNDER PRESSURE THERETO FOR MOVING SAID PISTON IN ONE DIRECTION, A SECOND HYDRAULIC CIRCUIT CONNECTED TO SAID CYLINDER ON THE OTHER SIDE OF SAID PISTON FOR SUPPLYING HYDRAULIC FLUID UNDER PRESSURE THERETO FOR MOVING SAID PISTON IN THE OPPOSITE DIRECTION, EACH OF SAID CIRCUITS INCLUDING A TANK OF HYDRAULIC FLUID UNDER REGULATED PRESSURE AND A HYDRAULIC PRESSURE BOOSTER CONNECTED IN FLUID FLOW AND PRESSURE TRANSMITTING RELATION TO EACH OTHER AND TO SAID CYLINDER SO THAT SAID CYLINDER AND SAID BOOSTER ARE SUPPLIED WITH HYDRAULIC FLUID UNDER TANK PRESSURE, AND A VALVE IN THE HYDRAULIC CONNECTION BETWEEN SAID CYLINDER AND SAID TANK WHICH IS ARRANGED TO CLOSE UPON ENERGIZATION OF SAID BOOSTER TO PREVENT THE TRANSMISSION TO SAID TANK OF PRESSURE GENERATED BY THE ENERGIZATION OF SAID BOOSTER, SAID VALVE INCLUDING A SPRING BIASED VALVE MEMBER NORMALLY POSITIONED TO PROVIDE FLUID FLOW FROM SAID CYLINDER TO SAID TANK UPON DEENERGIZATION OF SAID BOOSTER, THE PRESSURE IN THE TANK OF THE CIRCUIT FOR EFFECTING THE RETRACTILE STROKE OF SAID TOOL BEING SUBSTANTIALLY HIGHER THAN THE PRESSURE IN THE OTHER TANK SO THAT SAID TOOL IS NORMALLY RETRACTED WHEN SAID BOOSTERS ARE DEENERGIZED. 